The costs associated with the transportation of freight are high. One way of reducing these costs is to eliminate deadheading which involves making a one-way empty trip for lack of suitable freight for the freight carrier.
Dual-purpose road tankers for avoiding deadheading have been in operation in countries like Finland, Norway, Denmark, Sweden, Russia for some time. These have been manufactured mainly for the transport of fuel to forestry operations and then forestry products back to market. These dual-purpose road tankers are configured to allow the support of general dry freight on top of liquid tanks. With the introduction of new ADR (Agreement on Dangerous Goods by Road) regulations in 2004, all new road tankers built need to comply with these regulations which require inter alia: more pronounced roll over protection clearances on the top side of tanks; minimum tank shell thicknesses for tanks and bulkheads and tank ends; and minimum and maximum radii on tank shells meaning these road tankers need to be elliptical in cross-sectional profile and cannot have the squarish cross-sectional profiles or flatter (large radius) sides that were previously possible.
The resultant elliptical tanks do not lend themselves to transporting general dry freight on their top sides as these top sides are radiussed and are not flat.
It is an object of the present invention to provide a dual-purpose freight carrier which avoids the problem of deadheading and which is able to operate within transport vehicle height, width and length restrictions, while still at the same time complying with the abovementioned ADR regulations, providing a safe centre of gravity while transporting freight and providing for ease of loading and unloading of freight.